Who gets custody if one parent dies?

[casa]

My husband has been part of the child's life since the day he was born! The mother did not let him have any overnight visits, that is why he took her to court for visitation. The state went after him for child support after he signed the paternity agreement. He has always helped the family out in anyway he could. They are just bitter because he did not feel at the time that marriage was right for him and he chose not to marry. He loves his son very much and it hurts him that his son may loose his mother! My husband understands this he lost his mother to cancer too, he was 13 at the time! There is only the grandma, no grandpa involved! Can my husband set up some order/agreement with the courts that if something happens to the mother, custody goes to him? He is not looking to fight the ex for fully custody. He wants the son to stay with the mother, but if something happens he wants his son to be a part of our family, with his new step sister. His son even calls me mommy!

So, the visitation order was just established in 2004, but he was actually in the child's life all along?

If he took Mom to court for visitation~ Then there IS a custody and visitation order.